Alopecia 2 Flashcards
Inflammatory alopecia
Demodicosis
Bactieral infection
Dermatophytosis
Demodicosis
Caused by mites
Demodex canis, cati, gatoi
Normal skin flora from dam - EXCEPT gatoi
Proliforation of mites —> follicular inflammation = hair falls out spontaneously, predisposes to secondary deep pyoderma
Junvile onset for canine demodicosis
Juvenile or adolescent (first 18 months)
Treatment not required for localized form
May become generalized & requires treatment
adult onset of canine demodicosis
Develops spontaneously or due to underlying condition
Chronic steroid therapy
Hyperthyroidism
HyperADC
Chemotherapy
Requires treatment**
Localized - junvile demodicosis
<4 skin lesions ≤2.5cm
Erythema +/- gray hyperpigmentation
Comedones
Face and front limbs
Generalized - adult onset of demodicosis
≥5 skin lesions
+/- deep pyoderma
Furuncles (boils), draining tracts, lymphadopathy, fever, anorexia
Not pruruitc UNLESS - secondary pyoderma, host reaction to mites
Face, feet, dorsal trunk
Demodex injai
Long bodied mite species
Mainly in sebaceous glands/ducts
Common in terriers
Greasy coat on dorsal trunk
DX for injai
Deep skin scrapings - multiple sites
Trichogram - examine hair
Exudate exam - suppurative lesions
Tape impression + squeezing skin
TX for demodicosis
Mitaban - only approved, sedation, hypotension hypothermia
Ivermectin, moxidectin - neutro tox XX in MDR1
Milbemycin oxime - off label
Imidacloprid - off label
Prevention for demodicosis
Fluralaner - bravecto - off label
Afoxolaner - nexgard - off label
Sarolaner - simparica - off label
Lotilaner - credelio - off label
1/30d
When to stop treatment for demodicosis
Two scrapes - one month apart - both neg
Recurrence is common
“Cure” = one year without recurrence
Feline demodicosis
Demodex cati
Follicular mite, 2nd - steroids, FIV, FeLV)
Deep skin scrape
Oral ivermectin
Lesion for Demodex cati
Non pruritic alopecia patches
Alopecia, erythema, papules, mild pruritus
Mild scaling, follicular casting
Demodex gatoi
Pruritic & contagious mite**
Lives in stratum corneum
Only small might can be found
Superficial skin scrapes, fecal floats
Tx: lime sulfur dip
Skin lesions for Demodex gatoi
Pruritus, self induced alopecia, exocoriation, Miliary dermatitis, crusting,
Dermatophytosis
Caused by
Microsporum Canis (host —>cat)
Microsporum gypseum (geophilic —> soil)
Trichophyton mentagrophyts (host-> small mammal)
Transmission of Dermatophytosis
Direct contact w infected host, fomites, contaminated enviro
Fungal spores are viable for moths
Young, old & immunosuppressed are at high risk
Asymptomatic carriers of Dermatophytosis
Cats**
lesions of Dermatophytosis
Patches of alopecia + erythema
Lesions can expend centrifugally
Pruritus: varies, depends on hosts immune reaction
Mild scaling or crushing
Focal, multifocal, generalized
DX for Dermatophytosis
Woods lamp
Trichogram exam
Fungal culture
PCR
Woods lamp
Microsporum canis is the species that will
fluoresce
Hair fluoresce with a green apple color at
their base
Lack of fluorescence does NOT rule out
dermatophytosis
Trichophyton mentagrophytes and
Microsporum gypseum do NOT fluoresce
Requires experience
Trichogram exam
May reveal fungal spores and hyphae
Requires experience to recognize them
Fungal culture
GOLD STANDARD**
Hair shaft and scales are inoculated onto
dermatophyte test medium (DTM)
A color change from yellow to red within 2-3
weeks indicates positive fungal culture
>97% of M. canis causes color change within
14 days
Saprophytic (non-pathogenic) fungi can also
cause color change, but usually after 4 weeks
Importance of ID species in fungal culture
Other DX are not specific
Location & preventative measures need to be specific
PCR
Advantage: Easy, results within 1-3 business
days
Results reported as positive/negative for DNA
of Microsporum spp. or Trichophyton spp
Method of sampling: hair plucks, skin scrape
and brushing of the hair coat with sterile toothbrush
Shampoo for Dermatophytosis
Miconazole, ketoconazole, Terbinafine
Dilute leave on solutions for Dermatophytosis
Enilconazole - not in US
Systemic treatment for Dermatophytosis
Ketoconazole - GI, liver tox
Fluconazole - cheap, ex out kidney
Itraconazole - expensive
Terbinafine - cheap, least ADR
Griseofulvin - Myelosuppression
Environment treamtnent of Dermatophytosis
Prevents spread of infection to susceptible
individuals (animals and human)
Prevents false positive DTM and PCR (due to
inoculation of spores from the contaminated environment
All bedding, brushes, rugs etc should be
discarded, or washed in 1:10 to 1:100 dilute
chlorine bleach
Ischemia alopecia
Cells of lower hair follicles and epidermis
rely on diffusion O2 and nutrient from blood
vessels in the dermis
Disruption of blood supply results in hypoxia of
the cells which the vessels supply to
Skin lesions will vary and depends on the
1. Location (superficial vs deep)
2. Size of the vessel (large vs small)
3. Degree of disruption (partial vs complete occlusion)
Vaccine associated alopecia
Etiology: vaccine-induced, most often rabies
Skin lesion: Alopecia at the site of vaccination, hyperpigmentation may be seen
Diagnosis: history, biopsy of the center of the alopecic lesion
Treatment: none, usually will spontaneously resolve (may recur with future vaccination)
Dermatomyositis
Common is collies, Shetland sheepdogs
Lesions of Dermatomyositis
alopecia, erosion, ulceration, scarring on face (muzzle and periocular), ears and tail tips
Other signs of Dermatomyositis
muscle weakness/atrophy, regurgitation (megaesophagus)
Diagnosis: skin biopsies
Tx w immunosupprsions
Generalized ischemic Dermatopathy
Etiology: unknown
Skin lesions: Nearly identical to those of dermatomyositis but more generalized
Other signs: lethargy, muscle weakness • Diagnosis: skin biopsies Treatment: cyclosporine (5-10mg/kg/day) +/- immunosuppressive dose of oral steroids,
pentoxifylline
